Intraoperative myocardial device and stimulation procedure

ABSTRACT

A method and device for causing angiogenesis in the heart including the formation of a pattern of stimulus pockets or zones and channels. Laser energy is deliverable through one or more fiber optic elements at a controlled penetration depth and direction. The fiber element of the device is advanced incrementally within the myocardium. Laser bursts are triggered at intervals to create stimulus zones and/or channels.

FIELD OF INVENTION

[0001] This invention relates to the field of laser surgery, and moreparticularly to improved laser surgical methods and apparatus forincreasing or stimulating revascularization or angiogenesis ofmyocardial heart tissue and thus the flow of blood to heart muscle.

BACKGROUND OF THE INVENTION

[0002] Using various surgical techniques, some of which have been widelytaught, medical science has developed several procedures forcounteracting the effects of cardiovascular disease including open heartand bypass surgery.

[0003] More recently, another alternative form of cardiovascular surgeryhas been developed which is known as Transmyocardial Revascularization(TMR). Generally, in this TMR procedure, the surgeon accesses thepatient's heart by either percutaneous means or by an open incision,then proceeds to utilize a laser apparatus for creating a plurality ofchannels in the myocardial muscle tissue that forms a wall of a majorheart chamber such as the left ventricle. Clinical tests have shown thatthe creation of a plurality of channels serves to increase flow of bloodto the myocardial muscle tissue so as to establish a new vasculaturethat enables the heart to absorb more oxygen and be revitalized. Variousforms of TMR procedures are disclosed in prior art United States patentssuch as Pat. Nos. 4,658,817 (Hardy), 5,125,926 (Rudko, et al) and5,380,316 (Aita, et al) and also, more recently in co-pendingapplication Ser. No. 08/607,782 which is assigned to the assignee ofthis invention. All of the aforesaid patents and applications disclose aprocedure which utilizes laser energy that ablates the myocardial tissueat spaced apart locations to consume it in order to form a plurality ofchannels in the wall of the ventricular chamber of the patient's heart.As blood flows into each channel formed, a revascularization processtakes place which supplies additional oxygen to the heart muscle tissueand thereby revitalizes it. Although the beneficial effects of creatingsuch channels in the wall of the patient's heart chamber have beenestablished, certain risks involved with such procedures have also beenrecognized. For example, if too many channels are formed during oneprocedure, there is a risk that a certain patient's heart will reactnegatively to the trauma of the procedure or become weakened by it insome manner.

[0004] The present invention solves the aforesaid problem by providing amethod and apparatus that enables the surgeon to stimulate themyocardium to cause revascularization rather than ablate the tissue atseveral locations to create channels. Thus, for some patients, thestimulation procedure creates a revascularization effect whichstrengthens the heart's myocardial muscle tissue without negativeeffects thereto.

[0005] It is therefore one object of the invention to provide animproved method and apparatus for causing transmyocardialrevascularization by stimulating the myocardium with less laser power,by creating temporary channels with diameters sized so the channels willclose with time, and by creating spaced apart stimulation zones withinthe myocardium.

SUMMARY OF THE INVENTION

[0006] The present invention covers a method and apparatus forTransmyocardial Revascularization (TMR) procedures which provides forstimulating the myocardium of the heart muscle rather than creating openchannels in it as in prior TMR procedures. Within the context of thepresent invention, the term “stimulating” or “stimulus” means a TMRprocedure wherein channels, zones or pockets of lased tissue are formedin the myocardium which are not open, or do not remain open, to theventricular chamber of the heart. Revascularization or angiogenesis ofthe lased channels, zones or pockets occurs by means of introduction ofblood born growth and healing factors and stimulated capillary growthsurrounding the lased zones or pockets to create an increased supply ofoxygen to the tissue and thus a revitalization of the heart muscle.

[0007] Revascularization or angiogenesis of the lased channels and/orzones will occur in the following ways: First, blood born growth andhealing factors can be introduced to the site of stimulus (injury) asblood follows a lased or mechanical channel created by a laser fiber.The source of new blood and growth factors may be from the ventricle orfrom the surrounding myocardium. This combination of laser inducedinjury and blood born healing factors will act together to triggerrevascularization. Secondly, the human myocardium displays elements ofcertain direct blood pathways similar to those found in reptilianhearts. In the present invention these pre-existing pathways can beinter-connected by using stimulus and lasing pockets in the myocardium.The overall effect is to increase the opportunities for capillary bedsto become interconnected. Development of collateral coronary vessels iswell documented in coronary literature. This can be viewed as anenhanced means for promoting new vessel growth. Lastly, the coronarymuscle may be previously injured, thereby creating angina pain for thepatient due to the net balance of blood flow and conditions left by aprior heart injury. By stimulating the heart, a new set of injuries(stimulus) is created which triggers a new healing response; in effect,re-injuring the myocardium in a controlled manner and re-initiating thehealing process. The healing response is accompanied by increased bloodflow from one of the first two methods outlined. The healing withstimulus occurs with or without the long term patent or open channelsand blood supply via a continuous TMR channel from the ventricle.

[0008] In one embodiment of the invention, an optical fiber having atapered distal tip is forced through the epicardium of the ventricularwall and into the myocardium. Once into the myocardium tissue, laserenergy is emitted from the distal tip of the optical fiber radiallyoutwardly at an angle from the longitudinal axis of the fiber element.

[0009] In another embodiment, a device with multiple, narrow opticalfibers is used to create a relatively dense pattern of stimulationchannels. In a third modification, the epicardium may be pierced with atapered needle for introduction therethrough of a flat ended fiber.Additionally, access through the epicardium may be made through a singlehole and a laser fiber tip may be angled in different directions tocreate several stimulation sites.

[0010] During a typical TMR stimulus procedure according to theinvention the distal tip of an optical fiber element is moved axially inincrements to various depths within the myocardium. At each incrementaldepth, the distal tip may also be rotated as a laser pulse is emittedradially outwardly from the axis of the optical fiber. Depending on theconfiguration of the distal tip the laser energy may be projected in aplurality of different directions from the fiber axis. During thisprocedure, the laser energy is at a relatively low level that limits itstravel distance within and the amount of ablation of the myocardialtissue. Each beam or burst of laser energy from the distal tip of thefiber creates a partially ablated pocket or zone wherein angiogenesiscan occur due to capillary action within the pocket. Thus, for eachpenetration of the fiber element within the myocardium a pattern ofstimulus pockets or zones are created in the tissue surrounding thefiber element. Alternatively, stimulation may be created by alternatinghigh and low power pulses to predisposed channels that do not remainpatent. In a typical TMR stimulus procedure a plurality of stimuluspenetrations (e.g. 20-40) in the heart wall are made at spaced apartlocations and each penetration may produce 10-20 temporary channels,pockets or zones at various depths and at different locations around theoptical fiber axis. Yet, in accordance with the invention the distal tipof the optical fiber need not penetrate through the endocardium into theventricular chamber, although such penetration is not excluded.

[0011] A device according to the invention, for controlling thepenetration depth and direction of the laser energy comprises ahand-held instrument controlled by the surgeon. Within a body portion ofthe device a shuttle grips the fiber element to facilitate its forwardand backward movement in increments. Using the device the surgeon canadvance the fiber element incrementally within the myocardium as laserbursts are triggered at intervals to create stimulus zones. The fullaxial travel of the fiber element can be preset to limit such travel toan amount less than the thickness of the myocardium. In accordance withthe invention the hand-held instrument may control the axial movement ofa fiber element by mechanical or electrical means.

[0012] Other objects, advantages and features of the invention willbecome apparent from the following detailed description of embodiments,presented in conjunction with the accompanying drawing.

DETAILED DESCRIPTION OF DRAWING

[0013]FIG. 1 is a diagrammatic view of a heart, partly in section, andshowing a device for performing a stimulus type of TMR procedureaccording to the invention.

[0014] FIGS. 2A-2C are a series of enlarged views in section showing aportion of a ventricular wall of a heart as it progressively undergoes astimulus TMR procedure according to the invention.

[0015]FIG. 2A′ and 2B′ are views in section showing the pattern ofstimulated zones created by the device as shown in FIGS. 2A and 2B.

[0016] FIGS. 3A-3E are end views of various forms of optical fiber tipsused with a stimulus device according to the invention.

[0017] FIGS. 3A′-3E′ are fragmentary views in elevation of the opticalfiber tips shown in FIGS. 3A-3E.

[0018]FIG. 3F is a view in elevation of the distal end of a compositefiber element.

[0019]FIG. 3F′ is an end view of the fiber element of FIG. 3F.

[0020]FIG. 3F″ is a view in elevation showing the distal end of thecomposite fiber element of FIG. 3F as it appears after forming stimuluszones interconnected by smaller channels within the myocardium.

[0021]FIG. 4 is a view in perspective showing a stimulus deviceembodying principles of the present invention.

[0022]FIG. 5 is an enlarged fragmentary view in elevation showing aforward portion of the device shown in FIG. 4.

[0023]FIG. 6 is a further enlarged view in elevation and in section forthe device of FIG. 4.

[0024]FIG. 7 is an enlarged view in elevation and in section similar toFIG. 6, but showing the device of FIG. 4 in an alternate operating mode.

[0025]FIG. 8 is a view in perspective of an alternate form of TMRstimulus device according to the invention.

[0026]FIG. 9 is a fragmentary view in elevation and in section showinginternal components of the device of FIG. 8.

[0027]FIG. 10 is an enlarged fragmentary view in elevation of the distalend of a multi-fiber element for a stimulus device embodying principlesof the invention.

[0028]FIG. 11 is an end view of the multi-fiber element of FIG. 10 takenalong line 11-11 thereof.

[0029]FIG. 12A is an enlarged diagrammatic view showing a section ofmyocardium after stimulus treatment by the multi-fiber element of FIG.10.

[0030]FIG. 12B is a view in section taken along the line 12B-12B of FIG.12A.

[0031]FIG. 13 is diagrammatic view in elevation of a portion of a heartwall showing a single fiber element for creating stimulus zonesaccording to the invention.

[0032]FIG. 14 is a diagrammatic view similar to FIG. 13 showing stimuluszones of various sizes just after being formed in the myocardium byusing laser bursts at different power levels.

[0033]FIG. 15 is a diagrammatic view similar to FIG. 14 showing how thestimulus zones in the myocardium indicate a regenesis of capillarytissue after an elapse of time from the stimulus procedure.

DETAILED DESCRIPTION OF EMBODIMENTS

[0034] With reference to the drawing, FIG. 1 diagrammatically depicts across-section of a human heart 10 with the epicardium 12 of the outerwall of the left ventricle 14 exposed so that a stimulus type ofTransmyocardial Revascularization (TMR) procedure according to theinvention can be performed. Preliminary to the procedure the surgeonmakes an incision or a port in the patient's chest to access or exposethe outer wall (epicardium) of the heart's left ventricle. In, a humanheart, the wall of the left ventricle is comprised of an outer layer orepicardium 12, the main muscle thickness or myocardium 13, and the innerlayer or endocardium 15. The epicardium is comprised of a smooth, moistserous membrane which is somewhat tougher than the other tissue layersof the heart muscle.

[0035] In carrying out the method of the present invention, the surgeonmay utilize a hand-held device 16 which is manipulated and operated tomake a series of penetrations through the epicardium and into themyocardium of the patient's heart at selected spaced apart locations toform a multiplicity of stimulus zones 17. In this entire stimulusprocedure there is no need to penetrate the endocardium layer into theventricle cavity of the heart, although such penetration is notexcluded.

[0036] In accordance with the principles of the invention, eachpenetration of the heart wall is made by piercing the epicardiummembrane 12 with the distal end 18 of an optical fiber element 20, or bylasing through the membrane to form a relatively small opening or slit.Thereafter, the optical fiber can be moved with axial force by hand, orby any hand held device such as device 16 which can advance or reversethe fiber element by means of a movable control member 22 on the device16 when operated by the surgeon. The optical fiber element is connectedto a laser energy source 23 at its proximal end. Once through theepicardium opening and into the myocardium, laser energy is emitted fromthe distal tip 18 of the fiber element as it is moved forwardlyincrementally through the myocardium to a preselected distance from theendocardium. As the distal end 18 of the optical fiber is moved to eachincremental depth, it pauses momentarily while energy is emitted from itin a plurality of radial directions from the axis of the fiber. Each rayor segment of the laser energy emitted creates a partially ablatedstimulus zone 17 to increase vascular regenesis in the myocardiumtissue. After each penetration has been accomplished to form a pluralityof stimulus zones, the distal end of the fiber bundle is retracted to aposition within an enlarged stop member 24 at the outer end of thedevice 16 which can then be moved to another location to repeat theprocedure. When the distal end 18 of the optical fiber element 20 isremoved, the relatively small opening in the epicardium substantiallycloses due to the tissue resiliency, thereby minimizing any blood flowfrom the original penetration.

[0037] As shown in the embodiments of FIGS. 1-9, the optical fiber is asingle strand preferably having a diameter of 0.5 mm to 2 mm. Otherembodiments for accomplishing stimulus procedures using multi-strandoptical fiber elements will be described below relative to FIGS. 11 and13. In accordance with principles of the invention, the distal end 18 ofthe single optical fiber 20 may be tapered to a sharp tip to facilitateits passage through tissue of the heart by first mechanicallypenetrating the epicardium membrane and then moving by increments intothe myocardium. Alternately, laser energy may be used to penetrate theepicardium.

[0038] The sharp distal tip 18 on the optical fiber 20 may be formed indifferent configurations, as shown in FIGS. 3A to 3E, by polishing itsdistal end 18 with conventional apparatus well known to those skilled inthe art. For each tip configuration the direction and/or dispersion ofthe laser beam from the longitudinal axis of the optical fiber isdifferent. In FIGS. 3A and 3A′, an optical fiber 20A has a distal tip18A that is beveled to form a single end face 19 which is in a planethat cuts across the optical fiber axis at a preselected angle, e.g.45°-60°. Here, the laser beam (indicated by the dotted line) hits theend face 19 and is deflected inwardly from the fiber axis in a singlebeam at an angle that is 75°-90° to the end face.

[0039] FIGS. 3B and 3B′ show a single optical fiber 20B with a wedgeshaped distal tip 18 a formed by two facets 19 a that are in planes thatintersect the fiber axis at equal angles so that the wedge shaped tipsubtends an angle of around 60°-75°. Here, laser energy is inwardlyreflected from each of the two facets to opposite sides of the opticalfiber 20 a as indicated by dotted lines.

[0040] FIGS. 3C and 3C′ show a distal tip 18 c having three equal facets19C, and FIGS. 3D and 3D′ show a distal tip 18 C having four equalfacets 19D. In each case, the facets of the embodiments preferablyintersect the fiber axis at the same angle (e.g. 45°-60°) and thereforehave the same area and shape. The distal tip 18 c with three facetscause laser energy to be directed inwardly and radially from the fiberaxis in three substantially equally spaced apart directions and distaltip 18′d with four facets causes laser paths in four radial directions.

[0041] In the embodiment of FIGS. 3E and 3E′, a conical distal tip 18Eis provided which dispenses laser energy radially from the fiber axis ina 360° array and at a reflective angle from the angle of taper which maybe from 45°-60° with respect to the fiber axis.

[0042] From the foregoing it is seen that depending on the selection ofthe distal tip for the axially movable optical fiber a preselectedpattern of laser energy can be emitted from the distal tip into themyocardium tissue surrounding the optical fiber. As illustrated in FIGS.2A-2C, the optical fiber element 20 which may have any tip configurationas shown in FIGS. 3A-3E, is moved by increments through the myocardium13 to various depths within the tissue, but does not need to go throughthe endocardium 15 into the ventricular chamber. As shown in FIG. 2A, atubular neck portion 26 through which the optical fiber element 20 isslidably retained is first positioned adjacent a target area on theouter surface of the heart. With the stop member 24 against the outersurface, the fiber element is advanced forwardly through the epicardium.After penetrating the epicardium and reaching the myocardium, a burst oflaser energy is initiated to cause the distal end 18 of the opticalfiber 20 to disperse the energy radially in different directionsdepending on the distal tip configurations. If a single facet or wedgeshaped double facet configuration is used, the optical fiber can berotated a preselected amount at the same level to increase the number ofradial stimulus paths. The optical fiber element is advanced in shortintervals followed by a burst of laser energy from its distal tip, asshown in FIG. 2B. Every laser beam segment which is reflected from adistal tip facet forms a limited path through the myocardial tissue,partially ablating the tissue creating a pattern of zones or pockets 17as shown in FIGS. 2A′ and 2B′ wherein revascularization is stimulated byan increased capillary stimulus. The result is a regenesis ofreoxygenated tissue that increases strength and vitality in themyocardium, the major heart muscle tissue.

[0043] Summarizing the action of the optical fiber element 20 during aheart muscle stimulus procedure according to the present invention, thetapered distal tip 18 is first positioned adjacent to the epicardium ofthe patient's heart. The optical fiber is then moved forward topenetrate through the epicardium, or laser energy is used to penetrateand enter the myocardial tissue. At this initial depth, a burst ofenergy is triggered and is emitted from the distal tip into themyocardial tissue at radially spaced apart locations. The fiber elementmay be rotated to increase the number of stimulus zones prior to anotherburst of laser energy. Thereafter, the fiber element is moved forwardlyto another depth where another burst of laser energy is triggered. Theadvance, firing and rotation steps are repeated until the desired numberof stimulus zones are formed in the myocardium (See FIG. 2B). When thedistal tip of the optical fiber reaches a predetermined depth it iswithdrawn from the heart muscle wall, as shown in FIG. 2C, and movedlaterally to another location. As the distal tip is withdrawn from theepicardium, only a small opening remains which tends to close by virtueof tissue resilience so that little if any bleeding occurs.

[0044] The laser energy used in the stimulus procedures according to thepresent invention may be provided by a variety of laser systems. Apreferred system is a Holmium:YAG laser having a wavelength range ofapproximately 1.8 to 2.2 um.

[0045] In another form of the invention, a composite optical fiberelement 20F may be used which is comprised of a bundle of fiber strands.As shown in FIGS. 3F and 3F′, the composite element 20F has a largercentral strand 21 having a diameter of around 0.6 mm which is surroundedby a plurality (e.g. 6) of smaller strands 23 each having a diameter ofaround 0.2 mm. Here, the laser system, such as a low power HO YAG laserof 0.6 J or less, operates at 10 Hz at a single wavelength but with twopower level settings. The first power level with less ablating power,approximately 0.6 J, is delivered through the central strand 21 forapproximately two pulses to create a narrow stimulation channel 25having a diameter sized to form a temporary channel. The laser ispreprogrammed to automatically deliver from the outer ring of fiberstrands 23 a second power level with greater ablating power,approximately 1.2 to 1.65 J, or more, for approximately two pulses tocreate the stimulation pocket 27. Thus, as shown in FIG. 3F″, a seriesof pockets 27 interconnected by narrow channels 25 are created duringone penetration procedure. Alternately, the fiber optic element may beadvanced by hand to a selected depth in the myocardium and alternatinglow and high power energy may be activated during retraction. It will berecognized by those skilled in the art that other lasers and laserdelivery means may be used to create the pockets 27 and temporarychannels 25, including laser systems having two different lasers. Forexample, an argon or Nd:YAG laser may be used for the outer, smallerstrands 23, and a HO; YAG laser for the central strand 21. Pulses ofthese lasers can be programmed to alternatively deliver laser energyfrom the two lasers to form the stimulus pockets as shown.

[0046] The hand-held device 16 for controlling the aforesaid incrementaladvancement and laser firing of the optical fiber element to producemyocardium stimulation will now be described in greater detail. In theembodiment of FIGS. 4-7, the advancement device 16 is mechanicallyoperated. A power operated device 16A is shown in FIGS. 8-9.

[0047] The mechanical advancement device shown in FIGS. 4-7 includes agenerally pistol shaped housing 30 having a handle portion 32, a topaperture 34, front and rear apertures 36 and 38, respectively, and anoperating lever 40. The neck portion 26 of the device 16 serves as acarrier tube for the axially movable optical fiber element 20. It hasthe stop member 24 at its outer end, and at its inner end is shaftportion 42 with a series of spaced apart circular grooves 44. As shownin FIG. 5, a tube locking member 46 is pivotally mounted by a pin 48 onthe housing 30 and has a dog member 50 spaced forwardly from the pin. Atthe other end of the tube locking member 46 is a spring 52 which urgesthe dog member 50 into locking engagement with a selected groove 44 onthe tube shaft 42. Release of the locking member 46 for the lasercarrier tube 26 is accomplished by thumb pressure on the locking memberabove the spring. The laser tube 26 is movably mounted in a bore supportchannel (not shown) in the interior of the housing 50, so when thelocking member 46 is disengaged, the tube 26 can be adjusted axially.The carrier tube's axial position controls the length of the opticallaser fiber 20 that is exposed or the distance “D” of the distal tip 18from the stop 24. This distance “D” of fiber exposure from the stop 24corresponds to measurements of the thickness of the myocardium and thedesired depth of stimulation fiber element into the myocardium.Generally, this distance “D” varies between approximately 0 to 3 cm andis set by first depressing the locking member 46 to release it and thenmoving the tube 26 the desired distance.

[0048] Referring now to FIGS. 6-7, the means for controlling the forwardand backward axial movement of the optical fiber member 20 will bedescribed. Within the housing 30 a toggle mechanism 50 is provided whichis rotatably mounted on a pin 52 and includes a camming member 54. Thetoggle can be moved to one of two positions to determine the directionof movement of a reciprocating rack housing 56 which is fixed to thefiber element 20 which extends through the housing 50 from the laserpower source. The rack housing has an opening 58 with an upper rack 60of gear teeth and a lower rack 62 of similar gear teeth. Operativelyassociated with the rack assembly is a circular gear or one way ratchetwheel 64 fixed to the pivot end of the lever 40. The lever 40 and therachet wheel 64 are supported on an axle 66 fixed to the housing. Thus,it is seen that the fiber element 20 moves with the direction ofmovement of the rack housing 56. Pressing the lever 40 in the directionof the arrow in FIG. 4 when the toggle control 50 is in the positionshown in FIG. 6, causes advancement of the fiber element 20 from thedistal tip by engagement of the one way rachet wheel 64 and gear rack 62so that the rack housing moves in the forward direction “F”. Movement ofthe toggle 50 to the reverse position shown in FIG. 7 causes the cammingportion 54 to press downwardly on the rack housing 56 thereby forcing itdownwardly against compression springs 68. The one way rachet wheel 64now is engaged with the upper gear rack 60 to drive the rack in thereverse direction “R”. The compression springs 68 maintain the positionof the rack assembly within the housing 30. An optional laser firingbutton 70 may be provided on the housing handle 32 or the surgeon maycontrol laser firing by a conventional foot switch. The advancementdevice components such as the housing, control level, rachet, etc.preferably may be molded from a durable plastic material such aspolycarbonate or ABS.

[0049] The procedure for using the incremental laser advancement device16 may be described as follows. First the carrier tube is set so thatthe distal tip of the fiber element extends the maximum distance “D”from the face of stop 24. Distance “D” is determined as the thickness ofmyocardium less a certain amount in order to assure that distal tip 18will not puncture endocardium and emit laser energy into the leftventricular cavity. Now, the locking lever 46 is set on the tube byinserting its dog 50 in a groove 44 of tube. Fiber is retracted to thestarting point using the rachet housing 56. The device stop 24 is placedagainst outer heart wall. At this point either the distal tip 18 makesan immediate penetration through the epicardium or an initial forwardmovement using the advancing lever 40 moves the distal tip into themyocardium. The surgeon now fires laser to create stimulus zones. Thesurgeon then advances the fiber 20 in small increments firing the laserat each increment using a foot switch or the like to control the laser.

[0050] As an alternative procedure, the surgeon can move the distal tipthe full preset distance through the myocardium. Then, putting the rackhousing 56 rachet wheel 64 in the reverse mode, using the toggle 50, thedistal tip 18 is retracted in increments as the laser is fired at eachincrement to create the desired stimulus pattern.

[0051] As shown in FIGS. 8-9, an advancement device 16A may beelectrically driven, for example, by a DC gear motor 72 which is poweredby a battery 74 and controlled by a forward and reverse button switch 76and 77. Here, the output shaft of the motor 72 is connected to a gear 78that drives a meshed gear 80 connected to a lead screw 82 having ahelical grove 84. The lead screw 82 extends through a bore 86 in amovable carriage 88 which is fixed to the fiber element 20. Within thebase, the screw engages a follower 90 which is attached to the carriage.Thus, it is seen that rotation of the lead screw 82 drives the carriageand the fiber element back and forth. Fixed to one end of the lead screwis a cam 92 which engages and actuates a limit switch 94 for firing thelaser at preset increments of advancement and retraction. The limitswitch 94 may also be designed or wired to fire on advancement orretraction only. As shown in FIG. 8, the device 16A may also be providedwith a carrier tube 26A having a flared stop member 24A at its outer endas shown on the device 16. In use, the distal tip 18 of the fiberelement is positioned within the stop member during the initial contactwith the epicardium of the heart during each stimulus procedure.

[0052] As an alternative embodiment of the invention to the singlestrand or bundle version previously described, an optical fiber elementmay be provided which has a plurality of spaced apart strands. As shownin FIG. 10, an optical fiber element 20B has four relatively smalleroptical fiber strands 96 which project outwardly like an axiallyparallel, spaced apart group of prongs from a transverse stop member 24Bat the distal end of the fiber element 20B. Each of these smaller fiberstrands 96 has a diameter of around 0.1 to 0.5 mm and their distal tips18B may be blunt or beveled. The length of these optical prong-likestrands is roughly the estimated thickness of the myocardium, e.g. 1.5to 3.0 cm and despite their relatively small diameter these prong-likeelements are quite rigid. Inwardly from the stop member 24B the smallerfiber strands 96 are preferably held together by suitable pottingcompound 98 which is surrounded by a plastic sheath 100.

[0053] During a typical myocardial stimulus procedure using the fiberelement 20B, the fiber element is pushed against the outer wall of theheart ventricle until the distal tips 18B of the spaced apart projectingstrands 96 penetrate through the epicardium into the myocardium.Alternatively, laser energy may be used to penetrate the epicardium. Aswith previous embodiments, laser power is triggered to emit laser energyfrom the distal tips of the strands after they are moved forward inincrements to form stimulus pockets 102 beyond each distal tip withinthe myocardium tissue. As laser energy is emitted from the distal end ofeach fiber strand 96, following each interval of penetration, a patternof stimulus pockets 102 is created within the myocardium 13 as shown inFIGS. 12A and 12B. Alternatively, the relatively narrow fibers of thisembodiment may be used to create narrow temporary channels preferablyless than 0.5 mm in diameter.

[0054] In another modified form of the invention, a single optical fiberelement 20C having a diameter of around 0.5 mm is used. Here, as shownin FIGS. 13 and 14, the smaller fiber element which has a blunt orbeveled distal tip 18C is placed against the ventricle wall of theheart. Here, the fiber element 20C preferably extends through a tubularcarrier tube 26C having a flared stop member 24C at its distal end whichis provided with a hollow piercing member 104. The piercing member formsa small opening 103 in the epicardium membrane before the fiber elementis advanced through the piercing member into the myocardium 13. Onceinto the myocardium tissue, laser energy of relatively low power, 0.6 J,is transmitted through the distal tip to create a small connecting,temporary channel 105. Thereafter, a burst of laser energy of increasedpower (e.g. 1.2-1.65 J) is triggered from the distal tip of the fiberelement to form a larger stimulus pocket 106 (FIG. 14). As the distaltip of the fiber element moves forward and pauses, it emits alternatingbursts of low power and high power laser energy thereby forming a seriesof spaced apart stimulus pockets 106 of partially ablated tissueconnected by narrow channels in the myocardium. After the distal tip hasmoved to a position near the endocardium, the fiber element 20C isretracted and then moved laterally to an adjacent position to repeat theprocess.

[0055] After a period of time following the procedure illustrated inFIG. 14, the myocardium tissue naturally regenerates as shown in FIG.15. The opening 103 in the epicardium heals over and closes as do thenarrow channels 105, leaving the spaced apart zones 106 whereinregenesis of the capillary system occurs to revitalize the heart muscle.

[0056] To those skilled in the art to which this invention relates, manychanges in construction and widely differing embodiments andapplications of the invention will make themselves known withoutdeparting from the spirit and scope of the invention. The disclosure andthe description herein are purely illustrative and are not intended tobe in any sense limiting.

What is claimed is:
 1. A method for stimulating revascularization ofmyocardium tissue in the ventricular wall of a human heart comprisingthe steps of: providing optical fiber means having at least one distalend and at least one proximal end connected to a source of laser energy;moving the optical fiber means forwardly through the epicardium of theheart and into the myocardium; emitting laser energy from said distalend to form at least one stimulus injury within the myocardium of theheart to promote capillary growth and revascularization therein.
 2. Themethod of claim 1 wherein the step of providing optical fiber meansincludes providing a single optical fiber having a distal end shaped toemit laser energy in at least one radial direction relative to an axisof the optical fiber means.
 3. The method of claim 2 wherein the step ofmoving the optical fiber means forwardly includes the step ofincrementally advancing the fiber means.
 4. The method of claim 3wherein the step of emitting laser energy includes the step of emittinglaser energy when the fiber means is stationary.
 5. The method of claim1 wherein the step of emitting laser energy includes formation of one ormore pockets in the myocardium connected by temporary channels.
 6. Themethod of claim 1 wherein the step of emitting laser energy includesemitting laser energy at a first energy level to create at least onetemporary channel and emitting laser energy at a second energy level tocreate at least one pocket.
 7. The method of claim 1 wherein the step ofproviding optical fiber means includes providing a plurality ofparallel, spaced apart fiber probes each having a distal tip shaped toemit laser energy radially or in a generally axial direction.
 8. Themethod of claim 1 wherein the step of providing optical fiber meansincludes providing a central optical fiber surrounded by a plurality ofparallel optical fibers each having a diameter smaller than said centralfiber.
 9. The method of claim 1 wherein the step of providing opticalfiber means including the step of emitting laser energy from saidcentral optical fiber as said fiber means is moved forwardly in themyocardium to form a temporary channel therein and then emitting laserenergy from said plurality of outer fibers to form an ablated pocket inthe myocardium.
 10. The method of claim 1 wherein said central opticalfiber is connected to a Holmium HO:YAG laser source and said outerfibers are connected to an Argon Nd:YAG laser source.
 11. The method ofclaim 1 including the step of mechanically piercing the epicardium toprovide an opening for the optical fiber means to pass through into themyocardium.
 12. A method for stimulating revascularization of myocardiumtissue in the ventricle wall of a human heart comprising the steps of:providing an optical fiber means having a distal end and a proximal endconnected to a source of laser energy; moving said fiber means forwardlythrough the epicardium of the heart and positioning said distal end at afirst position within the myocardium; emitting a burst of relatively lowlevel of laser energy from said distal end in a radial direction fromthe longitudinal axis of the fiber means and for a limited distance toform at least one zone of partially ablated tissue within the myocardiumwhich stimulates capillary growth and revascularization therein; movingsaid fiber means from said first position to a second position andemitting another burst of relatively low level laser energy to form anadditional zone of ablated tissue within the tissue; and withdrawingsaid optical fiber means from the heart and moving it laterally toanother location to facilitate a repetition of the method steps.
 13. Themethod of claim 12 wherein said optical fiber means is a single strandwith a tapered distal tip.
 14. The method of claim 12 wherein saidoptical fiber means comprises a plurality of optical fiber strands thatare bundled together including a central strand surrounded by two ormore additional strands.
 15. The method of claim 12 wherein said opticalfiber means comprises a plurality of optical fiber strands which areaxially parallel and spaced apart and extend a preselected fixeddistance from a stop member.
 16. The method of claim 12 wherein saidfiber means is moved forwardly in small increments and stopped at eachincrement of movement as laser energy is simultaneously emitted from itsdistal tip to form a pattern of stimulus pockets within the myocardium.17. The method of claim 12 wherein said fiber means is first movedforwardly a preselected distance into the myocardium, then is movedrearwardly in small increments and stopped at each increment of movementas laser energy is emitted from its distal tip to form a pattern ofstimulus pockets within the myocardium.
 18. The method of claim 12wherein the laser power is derived from a Holmium:YAG laser having awavelength range of approximately 1.8 to 2.2 um and power level range ofapproximately 0.6 J to 1.65 J.
 19. The method of claim 18 wherein thelaser power level is varied from around 0.6 J to 1.65 J at increments ofaxial movement of said fiber means to create stimulation pockets in themyocardium.
 20. The method of claim 12 wherein said first position ofsaid optical fiber means is axially aligned with said second positionand laser energy is reflected radially from the distal end of saidoptical fiber means.
 21. The method of claim 12 wherein said firstposition of said optical fiber means is angularly displaced from saidsecond position of said optical fiber means.
 22. A device forrevascularization of the myocardium tissue in the ventricle wall of ahuman heart, comprising: a body member; a neck member connected to saidbody member; a flared stop member on the distal end of said neck member;an optical fiber means having a distal tip and a proximal endconnectable to a source of laser energy, said fiber means extendingthrough said body member, said neck member and said stop member; meanson said body member for moving said fiber means axially by increments tostop and position said distal tip at preselected positions relative tosaid stop member; and means for triggering the source of laser energy ateach said position of said distal tip to thereby create a zone ofpartially ablated tissue in the myocardium that stimulatesrevascularization of the tissue.
 23. The device as described in claim 22wherein said distal tip of the fiber means is tapered and pointed. 24.The device as described in claim 23 wherein said distal tip of the fibermeans has at least one outer surface that lies in a plane that forms anoblique angle with the axis of said fiber means, for deflecting thelaser beam transmitted with said fiber means radially outwardly from itsaxis.
 25. The device as described in claim 23 wherein said distal tip ofsaid fiber means has a plurality of outer surfaces, each surface beingin a plane forming a oblique angle with the axis of said fiber means,whereby multiple laser beams are deflected radially outwardly from theaxis of said fiber beams.
 26. The device as described in claim 22wherein said distal tip of said fiber means comprises a plurality ofparallel, spaced apart optical fiber prongs.
 27. The device as describedin claim 24 wherein said optical fiber prongs each have a diameter ofaround 0.1 to 0.5 mm and a length of around 1.5 to 3.0 cm.
 28. Thedevice as described in claim 22 wherein said optical fiber meanscomprises a central optical fiber surrounding by a plurality of outeroptical fibers having a smaller diameter than said central opticalfiber.
 29. The device as described in claim 28 wherein said centraloptical fiber has a diameter of around 0.6 mm and said outer fibers havea diameter of around 0.2 mm.
 30. The device as described in claim 28wherein said central optical fiber has a proximal end connected to anArgon Nd:YAG laser and said outer optical fibers are connected to aHolmium HO:YAG laser.
 31. The device as described in claim 28 whereinsaid central and outer optical fibers all have flat, non-tapered endfaces which are perpendicular to the fiber axis.
 32. The device asdescribed in claim 22 including a hollow piercing means connected tosaid stop member, said optical fiber means being movable axially throughsaid piercing means.
 33. The device as described in claim 32 whereinsaid optical fiber means has its proximal end connected to a laserenergy source which is operable at different, selectable power levels.34. The device as described in claim 22 including means for adjustingthe extension of said neck member from said body member.
 35. The deviceas described in claim 22 wherein said neck member has a proximal endportion slidably connected within a frontal aperture of said bodymember, said proximal end portion having a series of spaced apartcircular grooves, and neck adjustment means attached to said body memberhaving a locking means adapted to fit within a selected said groove tothereby retain said stop member at a preselected initial distance fromthe distal end of said optical fiber means.
 36. The device as describedin claim 35 wherein said neck adjustment means comprises a latch memberpivotally attached to said body member said latch member having alocking end projection at its outer end that fits in a selected groove,and a thumb actuated inner end portion connected to spring means forurging said end projection into engagement within the selected groove.37. The device as described in claim 22 wherein said means for movingsaid fiber means axially comprises a shuttle having first a secondspaced apart internal gear racks, a driving gear between said gear racksand connected to an operating handle, and means for urging said drivinggear into engagement with said first gear rack to move said fiber meansforwardly, and control means for alternatively moving said driving gearinto engagement with said second gear rack for moving said fiber meansrearwardly.
 38. The device as descried in claim 37 wherein said meansfor urging includes a series of springs extending between an interiorportion of said body member and said shuttle.
 39. The device asdescribed in claim 37 wherein said control means includes a pivotalmember having a cam portion adapted to bear against and move saidshuttle against said springs so that said driving gear engages saidsecond gear rack.
 40. The device as described in claim 22 includingelectrical power means for moving said fiber means axially, eitherforwardly or rearwardly.
 41. The device as described in claim 40including shuttle means fixed to said optical fiber means within saidbody member; helical drive means extending through said shuttle meansand rotatably supported within said body means; motor means for drivingsaid helical drive means to move said shuttle axially; and means forcontrolling said motor means so that said fiber means can be moved inincrements backwardly or forwardly.